Kinetic resolution of esters from secondary and tertiary benzylic propargylic alcohols by an improved esterase-variant from Bacillus sp. BP-7

•Esterase variant EstBP7-AGA efficiently overexpressed and produced.•New set of chiral benzylic propargylic esters synthesized.•Substrate diversity of EstBP7-AGA explored on new esters from secondary and tertiary alcohols.•Excellent E > 100 enantioselectivity obtained for pyridine-substituted tertiary alcohols.•Promising pharmaceutical building blocks may be obtained using esterase EstBP7-AGA.

We described in a recent work the rational improvement of an esterase from Bacillus sp. BP7 aimed at investigating the efficiency of several esterase variants for enantiomeric resolution of acetate esters of tertiary alcohols. Variant EstBP7-AGA, bearing two aminoacidic changes in the oxyanion hole, showed an excellent E > 100 enantioselectivity value towards a complex tertiary alcohol acetate (2-(4-pyridyl)-3-butyn-2-yl acetate) at low reaction temperature (4 °C). We here go further in the investigation of such esterase variant by analyzing the kinetic resolution of benzylic propargylic esters to prove that this enzyme is a powerful tool to obtain enantiomerically pure tertiary as well as secondary alcohols, provided that the structural integrity of the parent benzylic propargylic ester is maintained. Understanding the mode of action and interaction of such esterase variant with the assayed substrates will allow production of interesting pharmaceutical building blocks.

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